The title of the crime flick “2 Guns” is misleading. I thought it referred to Mark Wahlberg’s biceps, which, disappointingly, never make an appearance. Neither do the actor’s famously sculpted abs. Boo-hoo.

Wahlberg, nonetheless, is armed, and maybe a little dangerous in a movie that pairs him with two-time Oscar-winner Denzel Washington. As rogue agents working an undercover drug operation, the two studs arm “2 Guns” with double-barreled blasts of charisma, chemistry and million-dollar smiles. It’s the story that misfires.

Working with a script by Blake Masters that’s culled from a graphic novel, director Baltasar Kormákur (“Contraband” ) delivers a film that’s either full-blown fun or an out-and-out bore.

When Washington and Wahlberg share the screen, there’s rapid-fire banter and palpable chemistry. When the script forces them apart, the film stops dead in its tracks.

The plot – a ho-hum return-stolen-drug-money story – is a mess. It’s populated with too many villains, a rote romance and predictable twists and setups, that you can see coming 10 frames ahead.

That includes the inevitable reveal when Wahlberg’s Stig and Washington’s Bobby discover they are both undercover operatives sent to take down Mexican drug lord Papi Greco (Edward James Olmos, made up to look like a Hispanic Albert Einstein).

That effort leads them to rob a bank of $43 million, which puts another lawman (Bill Paxton) on their tails. Piling on the twists and turns doesn’t make “2 Guns” any more interesting. It creates confusion.

For his part, Paxton is deliciously sinister, bordering on camp. The rest of the supporting players, including James Marsden as a naval intelligence commander and Paula Patton as the token girl, add nothing but good looks. No fault of their own, because the script just isn’t there.

But it’s on par for August, which is generally considered a prime month for dumping bad movies. Ditto for January, which regrettably brought us Wahlberg’s “Broken City.”

Like that misfire, and “Contraband” a year before it, “2 Guns” proves to be a generic Wahlberg action flick, which Washington (“Safe House,” “Unstoppable”) is no stranger to, either. There are lots of explosions, gunfire, and wisecracks. Lucky for us, “2 Guns” isn’t deadly. It barely leaves a scratch.